Leadin bushing



Allg 4, 1953 L.. A. BORDE-N erm. 2,647,942

LEADIN BUSHING Filed pas. 1b. 194s B F 15.1 l

L 10B f E-E ,0 M

Patented Aug. 4, 1953 OFFICE LEADIN BUSHING Leland A. Borden, Riverside, and John C. Powelson, Cucamonga, Calif.

Application December 10, 1948, Serial No. 64,634

2 Claims.

The present invention relates to an improved leadin bushing particularly useful, although not limited thereto, as a means for conducting an antenna leadin through a building structure.

An object of the present invention is to provide an improved leadin bushing of the type described characterized by its simplicity, responsiveness, and ease of installation to produce a resulting water-proof seal rmly locked. i

Another object of the present invention is to provide an improved antenna leadin which is adaptable for any type of conductor, such as a twin-lead or coaxial conductor.

Still another object of the present invention is to provide an improved antenna leadin which, when installed, provides a weather-tight construction and eliminates bending and Charing of the leadin passing therethrough for obvious purposes.

Another object of the present invention is to provide an improved antenna leadin which introduces relatively low loss in the antenna circuit, has a pleasing appearance, and which may be used at the radio frequencies applicable presently to television and frequency modulation transmissions.

Another object of the present invention is to provide an improved leadin which does not require the use of sealing cement to obtain a weather-proof installation.

Yet another object of the present invention is to provide an improved antenna leadin, the installation of which requires no special tools or talent, only the use of a drill to drill a circular hole slightly greater in diameter than the diameter of the leadin bushing.

Still a further object of the present invention is to provide an improved leadin bushing incorporating novel fastening means whereby the bushing is prevented from becoming loosened in use in the installed building structure.

The features of the present invention which are believed to be novel are set forth with particularity in the appended claims. This invention itself, both as to its organization and manner of operation, together with further objects and advantages thereof, may be best understood by reference to the following description taken in connection with the accompanying drawings in which:

Figure 1 is a section through a building struc-A Figure 2 is a sectional view taken substantially on the line 2-2 of Figure 1.

Figure 3 is a view in side elevation of the leadin bushing embodyingthe present invention without the fastening nut mounted thereon.

Figure 4 is an end view of the structure shown in Figure 3, taken in the direction indicated by the lines 4 4; and

Figure 5 is a sectional view through a modied structure, indicating the manner in which the present leadin bushing may be used also for other types of cable such as a coaxial type of cable as shown in Figure 5.

Figures 6 and 7 are end and side views respectively of modified structures embodying features of the present invention.

Referring to the drawings, the leadin bushing embodied in the present invention comprises a tubular sleeve-like member I0 of high quality dielectric material such as polystyrene, with a nut Il also of polystyrene mounted on the special externally threaded portion IOA. Such threaded portion IUA is preferably of the socalled buttress or inverted empress type of thread for a purpose described presently.

The tubular member I0 is inserted through the building structure B which may be a wall or frame member of a house, after a circular hole I2 is drilled through the member B, the hole I2 being slightly greater than the external diameter of the body portion of the tubular member I0 to thereby provide a snug fit therewith. After such hole is drilled, the tubular member I0 is inserted in the hole l2 until the flange [0B engages the exterior surface I4 of the member B." Thereafter, the antenna leadin L, shown as a twin lead in Figures 14 and 2 and as a coaxial cable in Figure 5, is threaded through the, axially extending aperture 10D from the outside of the building into the inside, it being noted that such axially extending opening |0D has a cross section conforming to the outer contour of the leadin L and of slightly greater dimensions to allow the leadin L to pass therethrough but yet to provide snug engagement therewith. Thus, as shown in Figure 4, the central aperture IDD has a crosssection of dimension slightly greater than the cross-section of the twin lead antenna leadin L, shown in Figures 1 and 2.

An important feature of the present invention is that the end of the member I0, remote from the flange IUB, has a slit IUF along one of its diameters. Preferably, such diameter, as shown in Figure 4, corresponds to the elongated axis of the apertures portion IUD. The purpose of such slit IGF is to impart resiliency to the end of the member I0 upon which the nut Il is threaded. The nut Il when tightened on the threaded portion IGA thus causes the slit portions IIIG, IGH, divided by the slit IGF, to be resiliently pressed into engagement with the leadin passing through the central opening IOD to thereby firmly clamp such leadin in position and to also assure a weather-tight connection between the leadin and the bushing proper.

Upon tightening of the nut II, the flange IIIB is drawn tightly against the face I4 of the building structure B to provide a weather-tight connection between the building structure and the bushing I0, and, also, simultaneously the antenna leadin II is firmly clamped along an extended area to not only prevent subsequent movement of the antenna leadin but also to provide a Weathertight seal between the antenna leadin and the bushing. Such clamping of the antenna leadin is accomplished to advantage by the use of the buttress type of thread IDA, which thread serves also to prevent untightening of the nut IIA once it is tight. In other words, referring to Figure 2,. as the nut I I tends to become loosened, its initial motion is on the inclined planes dened by the contour of the thread IIIA with the result that the antenna leadin L is more iirmly gripped; and due to the resilient nature of the installation inaterial thereon, the motion of the nut I I is countei-acted so that consequently the nut I I is rmly maintained in fastened position.

In the modied arrangement, shown in Figures 6 and 7, the bushing serves also as a socket for receiving a cooperating quickly attachable and detachable plug. For this purpose, the twin lead does not extend entirely through the ends of the bushing I but has its opposite conductors connected electrically respectively to the female terminals 32, 33 releasably recessed in corresponding circular apertures 34, 35 in the end of the bushing I0. These terminals or sockets 32, 33 are of conventional resilient construction adapted to have connected thereto opposite conductors of the twin lead as, for example, by soldering and are adapted to snugly t into the circular recesses 34, 35. In assembling the twin lead and connectors 32, 33 in the modified bushing I0y initially the twin lead is pulled through the bushing I0 to allow opposite conductors thereof to be soldered to the terminals 32, 33 after which the twin lead and attached terminals 32, 33 are drawn into the bushing by pulling the twin lead to an extent wherein the connectors 32, 33 are recessed within the openings 34, 35. Thereafter, the twin lead is clamped by the nut II as previously described in connection with the other gures.

While the particular embodiments of the present invention have been shown and described, it will be obvious to'those skilled in the art that changes and modifications may be made without departing from this invention in its broader aspects and, therefore, the aim in the appended claims is to cover all such changes and modincations as fall within the true spirit and scope of this invention.

We claim:

l. In a leadin bushing adapted to lead an antenna leadin through building walls of widely varying thicknesses, the combination of a 1ongitudinally slit cylindrical tubular member adapted to be inserted through an aperture in a building wall, said tubular member having a flange at one of its ends adapted to engage one side of said wall and having a threaded portion at the other one of its ends upon which a nut is placed to engage the other side of said wall, said threaded portion comprising a buttress thread-of uniform pitch diameter and having the inclined nut engaging portions of said thread extending outwardly and inclined in the direction of the nut receiving end of said threaded portion, said nut having a buttress thread of uniform pitch diameter cooperating with the buttress thread on said threaded portion to cam opposed parts of said tubular member radially inwardly to clamp a portion of the antenna leadin disposed therebetween automatically when and only when said nut is rotated in contact with said other side of said wall.

2. The invention defined in claim 1 characterized by the fact that said tubular member incorporates a pair of electrical connectors recessed within said one of its ends and connected to opposite conductors of said antenna leadin.

LELAND A. BORDEN.

JOHN C. POWELSON.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 813,998 Braine Feb. 27, 1906 1,523,463 Thomson Jan. 20, 1925 1,890,348 Weatherhead Dec. 6, 1932 2,530,258 Marsan Nov. 14, 1950 FOREIGN PATENTS Number Country Date 175,707 Great Britain Mar. 2, 1922 205,227 Great Britain Oct. 18, 1923 319 905 Great Britain Oct. 3. 1929 

